Want to very highly recommend "The Presidents Club," written by Nancy Gibbs and Michael Duffy, to the forum.
It is a very detailed and extremely well-documented history of the relationships between past, present, and future presidents and how they interacted with one another before, during, and after their time in office. It's not always flattering about the individuals but also illuminates some very positive interactions, support, and advice (both solicited and given), even between presidents of different parties. Lots of info and, based on the extensive notes and attribution provided, lots of verifiable facts on their relationships, both positive and negative. I found it to be very credible and enlightening on the egos, character, and personalities of presidents from Hoover forward.

It put some entirely new light on the workings of each administration as they dealt with the awesome responsibilities of the office of POTUS. A GREAT READ!!